Vertebral Artery Groove in the Atlas
and Its Clinical Significance
542-545
Correspondence
Dr. D. Ravichandran MD (Anatomy)
Department of Anatomy,
Vinayaka Mission Kirupananda Variyar Medical College,
Salem, Tamil Nadu , INDIA
Ph. No: (0) 9952090673
e-mail: drravianatmd@gmail.com.
ntroduction: The vertebral artery groove is located on the superior surface of the posterior arch of atlas vertebra lodging the third part of the vertebral artery. The morphometric data of the groove including the groove length, width and thickness of the bone forming the floor of the groove is scarce in Indian literature. The distance between the groove and the posterior midline is of surgical importance. Iatrogenic injury to the vertebral artery is common in posterior approaches of the atlas vertebra. The objective of the present study is to obtain the morphometric data of the groove and to assess the distance of the groove from the posterior midline for providing a safety guideline to the surgeons.
Materials and Methods: 75 dry human atlas vertebrae were measured manually using vernier calipers. The morphometry of VAG and its distance from midline were evaluated through eight linear measurements. The results were analysed stastically using SPSS 16 version.
Results: The inner groove length was 7.71 mm and 7.49 mm on the right and left sides respectively. The outer groove length was 8.1 mm on the right and 8.24 mm on the left side. The mean width was 7.89 mm on the right and 8.08 mm on the left side. The mean thickness was 4.7 mm on the right and 4.55 mm on the left side. The safe zone from the midline during posterior approach to C1 to avoid potential injury to vertebral artery was found to be 11.26mm.
Discussion: Iatrogenic injury to vertebral artery is the most commonest per-operative complication during a posterior approach. The distance of the groove from the posterior midline and knowledge of the morphometric data of the groove is important for instrumentation procedures in the atlas vertebra.
Conclusion: The present study reveals the morphometry of the vertebral artery groove and recommends a safe zone of 11.26 mm from the midline in posterior approach for atlas vertebrae.